A photoelectric conversion layer is widely utilized in, for example, optical sensors and in particular, is suitably used as a solid imaging device (light receiving device) of imaging device (solid imaging device) such as a television camera. As materials of the photoelectric conversion layer which is used as the solid imaging device of imaging device, layers made of an inorganic material such as Si layers and a-Se layers are mainly used.
Conventional photoelectric conversion layers using such an inorganic material layer do not have sharp wavelength dependency against photoelectric conversion layer characteristics. For that reason, as to an imaging device using a photoelectric conversion layer, imaging devices of a three-plate structure in which a prism capable of resolving incident light into three red, green and blue primary colors and three sheets of photoelectric conversion layer to be disposed behind the prism are the main current.
However, imaging devices of such a three-plate type structure inevitably become large in both the dimension and the weight from the standpoint of structure.
In order to realize miniaturization and weight reduction of the imaging device, a device which is not required to provide a spectral prism and which is of a single-plate structure made of one sheet of a light receiving device is desired. For example, imaging devices of a structure in which red, green and blue filters are disposed in a single-plate light receiving device are studied. Also, it is studied to use, as a material of the photoelectric conversion layer, an organic material having such advantages that the kind and characteristic are diverse and that a degree of freedom in the processing shape is large. A photoelectric conversion layer having enhanced photosensitivity (sensitivity) and a light receiving device using the same are described in JP-A-2003-158254. According to JP-A-2003-158254, organic materials are used as a p-type semiconductor and an n-type semiconductor. However, in the working examples of JP-A-2003-158254, there is described only an example in which polymethylphenylsilane (PMPS) is used as a p-type organic material, an 8-hydroxyquinoline-aluminum complex (Alq3) is used as an n-type organic material, and coumarin 6 as an organic dye is added in an amount of 5.0 parts by weight based on 100 parts by weight of the foregoing PMPS. Furthermore, in the section regarding preferred embodiments in JP-A-2003-158254, it is merely described that the organic dye is preferably used in an amount of from 0.1 to 50 parts by weight based on 100 parts by weight of the p-type or n-type organic material which constitutes the photoelectric conversion layer. However, JP-A-2003-158254 does not describe that the organic dye is used as the p-type or n-type organic material.
Also, for the purpose of realizing miniaturization and weight reduction of the imaging device, JP-A-2003-234460 describes a stack type photoelectric conversion layer with a low resolution is described as a device which is not required to provide a spectral prism and which is of a single-plate structure made of one sheet of light receiving device. JP-A-2003-234460 describes that, for example, a preferred stack type photoelectric conversion layer is prepared by stacking a photoelectric conversion layer having a function to absorb light of a wavelength of any one color of three primary colors of light, a photoelectric conversion layer having a function to absorb light of a wavelength of one of other colors and a photoelectric conversion layer having a function to absorb the remaining color and that in this way, a color image having high sensitivity and resolution can be obtained.
However, in the working examples of JP-A-2003-234460, there is described merely a photoelectric conversion layer in which a coumarin 6/polysilane layer having photosensitivity over the whole of a blue region of not more than 500 nm and a ZnPc/Alq3 layer having an absorption region in not only a red region but also a blue region are used as photoelectric conversion layers, thereby having photosensitivity only over the whole of a substantially red region in the center of from 600 to 700 nm due to the filter function of the coumarin 6/polysilane layer.
Furthermore, JP-A-2003-332551 describes a stack type photoelectric conversion layer similar to the foregoing JP-A-2003-234460. However, JP-A-2003-158254, JP-A-2003-234460 and JP-A-2003-332551 do not describe that the dye according to the invention gives a preferred performance.